| Impact Summit Online | |
| Impact Technology UK Ltd | Greater London |
| Impact Web Design | West Yorkshire |
| Impactive Solutions | |
| ImpactVest | |
| Impelling Solutions Ltd | South Yorkshire |
| Imperial College London | Greater London |
| Imperial College London - Department of Computing | Greater London |
| Imperial College London - Department of Mathematics | Greater London |
| Imperial College London - Department of Electrical and Electronic Engineering | Greater London |
| Imperial College London - Structural Bioinformatics Group | |
| Impero | |
| Impero Solutions Ltd | Nottinghamshire |
| Impirius Ltd | Warwickshire |
| Implement Outsourcing Ltd | |
| Implicit Ltd | |
| IMPlog | Staffordshire |
| Impression | |
| Impression Digital Ltd | |
| Impreza IT | Kent |
| Improbable | |
| Improbable | |
| Improve My Search Ranking | |
| Improved Apps | |
| Impulse Automation Ltd | |
| Impulse Branding & Marketing Ltd | North Yorkshire |
| Impulse Embedded Ltd | Staffordshire |
| Imran Ghory | |
| IMRSV | |
| ImspexGroup Ltd | |
| IMsupporting Ltd | Gloucestershire |
| IMT Systems | |
| Imtech | |
| Imtex Technologies Ltd | Northamptonshire |
| IMU Biosciences | |
| Imyge Net | |
| Imzr Labs | |
| In Conference Ltd | |
| In Control | Greater London |
| In Front Digital | West Midlands |
| In House Media | Northamptonshire |
| In Studio Digital | |
| In-Form Consult | Hertfordshire |
| In-Parallel Computer Staff Ltd | Gloucestershire |
| In-Space Missions Ltd | |
| In-Tuition Networks Ltd | Oxfordshire |
| In.security | |
| In2 Computing Ltd | Greater London |
| In2Connect UK Ltd | Northamptonshire |
| In2tec Ltd | Northamptonshire |